Last month we looked at Leaf Mold, Mulch or Compost. That’s from the end of life of tree leaves. This month I would like you to take a think about Living Mulch! It is by contrast, an ongoing sustainable green process that produces more and more Nitrogen right where you can use it. It’s generally a faster process by far! You may be a little challenged to figure out how to use it in your specific garden, and you may choose not to, but it may be a perfect option for many reasons.

I use it for my strawberry patch each year. When weather cools and the berries produce little, I pull them, plant my living mulch, green manure, close to Oct 1 for mid January bareroot berry planting. If I have a soil area that is producing less than spectacularly, I plant that area about Dec 1 in time to be ready for early spring planting mid March. Clearly, if you are in northern snow zones, you may need to rotate areas, plant living mulch in an area every three years maybe. In SoCal you might forego planting a ‘winter’ garden and instead plant living mulch. It will need watering, but while it’s working hard to make great soil, you can have a wee rest.

Looking to find what plants to grow as a Living Mulch under Rat’s Tail Radishes started my inquiry! I was delighted to find this permaculture farm site with these terrific details based on experience with references to university (non commercial) research. It’s the real deal since their income depends on successful sustainable growing near Missoula, Montana in a northern short season!

Living mulch can easily be done by planting closely and letting the leaves of the plants completely shade your soil keeping it cool and moist. That might look like a row of beets or carrots, or differently colored lettuces in a patch! Or it can be done by planting an understory of smaller plants on the sunny side of a larger plant.

However, you can eat only so much of these smaller plants. What else could you do? You might like to prepare your current pathway for crop rotation – using it to plant in next season. Maybe you have an area you would like to convert to a veggie garden, or you have a patch where you want to restore the soil before planting again.

When you read this, you will think like a farmer! After you’ve got it, then think how to apply this info to your own garden. These excerpts from http://www.veganicpermaculture.com/agroecology.html have some more technical language and information, but take it slowly. Sometimes I have to read one paragraph at a time, several times, when I’m taking in new dense information. It’s worth the read. You won’t be the same afterwards, and there are some surprises. Go directly to their page to get the whole read, see all the backup images and videos! But read this too, because I’ve made comments for home gardeners and SoCal timing along the way and at the end….

You can grow your own fertilizer with living mulches. Living plants used as mulches have an advantage over dead mulches, such as straw and hay. They affect soils both above and below the ground. They grow with and around main crops and are usually green, succulent, and full of nutrients, with a well-developed root system. This root system works its way into the earth, opens up the soil, and feeds the soil food web all season long, if living mulches are managed properly.

Over time, living mulches improve soils and build the skeletal framework which holds plant nutrients so that they are available when plants need them. This is because living mulches add organic material into the soil without disturbing it. When mowed regularly or tilled into the soil, living mulches add plant nutrients for free, including the big three: nitrogen, phosphorus, and potassium, as well as sulfur, calcium, and micronutrients. When compared to plants grown without mulch in bare soil, legume living mulches produce higher vegetable yields. Leaf cover and yields of bush green beans was higher when planted into a killed stand of hairy vetch. Corn yields were higher in red clover that had been killed in strips. Though fruit maturity was delayed, yields of tomatoes grown in hairy vetch were higher and fruit weights were greater than in bare soil treatments.

Soil organic matter acts like a big sponge soaking up water and releasing it slowly when needed. However, in the short term, most living mulches steal soil water from crops when both are actively growing, especially early spring through early summer. Living mulches hold onto and recycle soil water when NOT actively growing. In one study, corn grown in mowed hairy vetch struggled for water during the first 1 to 4 weeks after planting. But, by two to four weeks after planting, soil moisture levels were the same as in bare soil treatments. Soil water levels were higher than in bare soil after four weeks. In other words, over time living mulches can conserve moisture in your garden, but in the short term, especially right after planting, they compete with crops for soil water.

Living mulches provide diversity and a legume crop rotation which is the foundation of disease suppression in all organic gardens and farming systems. In my 17-year living mulch vegetable production system, disease problems simply dropped off the radar, including cabbage worms. In a 2- year study, we discovered that the living mulch was providing a home for many kinds of predators who were controlling cabbage worms in our commercial plantings of broccoli, cabbage, and Brussels sprouts.

IMPORTANT to know! In cold, wet soil, living mulches may encourage disease and some pests such as slugs or snails. Researchers from South Dakota found lower seedling emergence and survival and higher amounts of disease-causing fungi in clover and hairy vetch mulched fields, when crops were planted during cool weather. But many other studies indicate that several insect pests are controlled in living mulch as compared to bare soil plots. Several species of both specific and generalist predator and parasite populations [the good guys] have been shown to increase in living mulch plots.

When hairy vetch and rye residues covered at least 90% of the soil in one study, weed density was decreased by 78%. Living mulches can fight weeds by “smothering” them, and by utilizing all the water and nutrients so that weeds are starved and cannot invade. Combinations of grasses and legumes are best for smothering weeds.

When to plant your Living Mulch – There are 3 kinds!

ANNUAL LIVING MULCHES. Plant in the spring. In cold climates they are killed by below freezing winter temperatures.

BIENNIAL LIVING MULCHES Plant in the spring. Will grow foliage the first season, overwinter and then flower, set seed, and die the next growing season.

PERENNIAL LIVING MULCHES Plant in late summer/early fall or in spring

You want to read this! For fascinating details on which plants to plant at which times and details about each so you make the very best choice, see their page.

Important points! Once you have chosen the right living mulch for your particular area and need, develop a management plan. You can keep living mulches from becoming too competitive by mowing, lightly tilling, rolling, or keeping them dry (withholding irrigation).

Mulches should be mowed and left to sit on the soil surface for two days to two weeks before incorporating into the soil. Your management timing affects pest management.

Keep mulches short in wet, humid weather to avoid disease.

Mow mulches if annual weeds begin to pop their heads through in order to avoid weed seed production.

For FAST plant nutrient cycling, till living mulches into the soil in late spring 2-4 weeks before planting.

Ok, so when you plant living mulch, say for your annual mid Jan bareroot strawberry patch…count back with me. Now this timing will vary depending on which living mulch plants you choose.

Mid Dec till in your living mulch for mid January bareroot planting. The little white balls on the roots are like a beautiful little string of pearls. Those are the Nitrogen nodules legume plants make!

About Dec 1 chop down/mow, chop up your living mulch and let it lay on the surface. If Bell beans are in the mix, chop when it flowers or the stalks will get too tough to easily chop into small pieces. Keep your chopped mulch moist, not wet, until it is tilled in. Being moist aids decomposition.

Oct 1 plant your living mulch – put this on your garden calendar! Bell beans take that long if they are in the mix or are your choice.

If you are preparing for early SoCal spring planting mid March, that translates to planting your living mulch, again based on your choice of plant(s), right about Dec 1. If you miss that window, plant a faster grower! Clovers and vetch grow quickly and vigorously, or ask your local nursery, feed store person or farmers what they have or what plant will do the job.

Legumes are prime living mulch choices because they make (fix nitrogen from the atmosphere) for other crops. But, they only give up that fixed nitrogen when they die or are tilled into the soil, or over time if they are mowed and the residue is left on the soil surface as a mulch. Actively growing legumes do not USE as much nitrogen as non-legumes, but they do not GIVE UP nitrogen to the soil or other plants when they are actively growing. Legumes do not fix nitrogen at equal rates, or under all conditions. Nitrogen fixation rates are decreased by low (< 40 to 50o F) soil temperatures and stop at freezing temperatures. Nitrogen fixation rates vary among legume species. For example, clovers, sweet clovers, medics, and vetch provide 0.1 to 2.5 lbs of nitrogen per 100 sq ft. Alfalfa provides six pounds of nitrogen per 100 sq ft.!

I use Island Seed & Feed’s Harmony mix – Bell beans, Austrian Peas, Vetch and Oats. Oats grow deep into the soil opening air and water channels, bring up nutrients. Get the inoculant that goes with it. After you broadcast your seeds, roll them or if a small space, lay down a piece of plywood or a board and press them into the soil so the seeds have good soil contact and will stay more moist longer when watered. Water gently overhead with a fine spray so soil isn’t washed away and soil contact lost, seeds aren’t swooshed to a low spot. Cover with raised aviary wire, or your choice of material, to keep them from being bird food! Keep them moist, especially if there is hot weather.

You can plant living mulch at any time, depending on your climate, among your existing plants. Living mulch plants shade the soil, some suppress weeds, while they are living, then feed the soil when you till them in after your plants are done. Just choose ones for the right time of year. Plant your garden pathways with ones that can stand being walked on. Till that in and plant there next season!

HOW AND WHEN TO CONTROL YOUR LIVING MULCH

The way living mulches are managed in our [Montana] gardens determines what benefits we derive from them. Legumes contribute most to soil fertility if they are mowed or tilled into the soil. Nutrient release is much slower if the living mulch is mowed and not tilled in. But, some studies indicate that nitrogen, calcium, magnesium, and potassium levels are best increased in the soil over the long term when crop residues are left on the surface, rather than tilled into the soil. Nitrogen release by cover crops depends on temperatures and humidity levels. The warmer the weather, the more quickly residues will release their nitrogen. Studies at North Carolina State indicate that 75% of the nitrogen in some legume cover crops is released within seven to ten weeks after mowing if residues are left on the surface. If the residues are tilled under, nitrogen release is quicker and may be accomplished within four to eight weeks. In cooler weather, nitrogen release can take much longer. In my experiments in Montana in a very microbially active soil, nitrogen release occurred 2 to four weeks after tilling red clover into the soil. There is a lag time of at least two weeks during which nitrogen and phosphorus will be tied up in the soil food web digesting wheel (This lag is called immobilization because soil microbes are using the same nutrients that plants need and thus immobilizing them, or making them temporarily unavailable to plants). Plan for this and wait two to four weeks after mowing or tilling the living mulch before planting main crops. Waiting at least two weeks to plant will also reduce the chance of increased disease organisms, which can be favored by an addition of fresh (particularly succulent and green) residue.

Mowed cover crop residue left on the surface to decompose needs to be kept moist (but not wet!) for at least the first five to seven weeks after mowing to enhance decomposition.

Some living mulches may need light tillage. Light tillage equates to walking your rototiller quickly over the surface of the living mulch. Do not let the tiller tines go into the soil more than one to two inches. If residue is buried deeper than several inches below the soil surface, decomposition time will be longer and anaerobic conditions may occur. Remember that soil microorganisms require oxygen to do their job.

Cover crops can also be managed with a rake. Rake the cover crop vigorously until the soil is exposed. Cornell University research indicates that disturbing living mulch cover crops by using light tillage is most successful in July. This is also the time when most summer crops are particularly resource demanding and hence it is a time when living mulches are most likely to compete with crops.

RIGHT INOCULANT FOR YOUR LEGUME COVER CROPS

Inoculation of legume cover crops is suggested. Inoculants consist of species-specific bacteria that associate with legume roots and fix atmospheric nitrogen. Use the correct inoculants for the cover crop. Alfalfa and yellow and white sweet clovers share the same inoculants; true clovers share another; peas and hairy vetch share a third; garden beans and field beans share a fourth. Purchase inoculants when purchasing seed.

Some living mulches are allelopathic. This means that they biochemically inhibit the growth of other plants. Mustard family types, such as rape and black mustard, are good examples of allelopathic living mulches. Allelopathy can be used to help control weeds; on the other hand, crops can be adversely affected, particularly seeded crops [meaning seeds don’t germinate well or at all].

Seeded crops, like lettuce, can be inhibited by some living mulches, such as mustard, but usually only if the living mulch is tilled into the soil and a crop seeded immediately after. The allelopathic reaction dissipates in time. For example, the compound in plants from the mustard family [includes Brassicas] that is most responsible for its allelopathic reaction loses 80 percent of its punch within two weeks. Plant main crops three to five weeks after mowing or turning under any living mulches suspected of exhibiting allelopathy.

Living Mulch is a superior choice. Give it some thought. Carefully read up on it. Keep your notes. Every gardener’s situation is different – what you grow, your weather, how much time you have, how much production you need. Living mulch is a sustainable choice.

There are two SoCal standard times to plant living mulch to do soil restoration. One is early October to be in time for January bareroot strawberry and berry vine plantings. The other is December/January for early spring plantings. Or you can opt to not plant an area for production that year and plant living mulch anytime if you live in an area that freezes in winter.

In Santa Barbara area, Island Seed & Feed carries legume seeds and mixes by the pound and the inoculants you need. Plus, it’s a fun place to visit! They also carry LOTS of other seeds and local organic seeds as well! (Pet supplies too!)

You don’t need to do a large area. Do a test run. This year try a pathway with living mulch you can walk on instead of a board, concrete steps or straw! If you do a pathway, mound it up before you plant so when it compacts as you walk on it, it will stay level rather than dipping lower and collecting water, making mud. Restore an area where you will grow heavy feeders next spring. When you are eating bigger tomatoes right off the plant you will be happy and feel quite virtuous.

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The Green Bean Connection started as correspondence for the Santa Barbara CA USA, Pilgrim Terrace Community Garden. All three of Santa Barbara city community gardens are very coastal. During late spring/summer we are in a fog belt/marine layer area most years, locally referred to as the May grays, June glooms and August fogusts. Keep that in mind compared to the microclimate niche where your veggie garden is. Bless you for being such a wonderful Earth Steward!

The graph above is of best soil temps for seed sowing! And even then, some seeds are more cold or heat tolerant, so get enough seeds to try again should there is some kind of fail.

Challenging conditions can be shady areas, or if you are intermingling veggies in your landscape, areas shaded by permanent ornamental plants. Transplants are already up and more hardy, sun reaching sooner, so your wise choice may be to start with transplants, not seedlings started outside. If you are container gardening, move your container to follow the sun during the day. Use one of those little plant dolly thingies if it is a heavy container.

String Beans

DARK AND LIGHT-SEEDED BEANS: Dark-seeded beans are more resistant to rotting in cool soil than light-seeded beans. Beans need a minimum soil temperature of 65F to germinate well, otherwise rotting may occur.

Beans are crazy to grow! They will give you a good crop in soil that’s loamy, sandy, rocky, rich or poor and even in clay as long as it has good drainage. They do prefer slightly acid soil. Though beans do need regular water for their short roots, still, avoid planting them in shade with soil that stays wet.

When growing beans in a new garden site! Special tip from Bountiful Container: ‘With inoculant, the critical bacteria that enhance the plant’s ability to convert Nitrogen from air into N in the soil, are added to the soil. Either powder the inoculant on wet seed or sprinkle granules in the soil along with seeds. Grow stronger, produce more beans.’ Even simpler, if available, scatter a few spadefuls of soil from last year’s bean patch into new planting sites.

Beans like days to be at least 70 degrees and nights to dip no lower than 40 degrees. It’s worthwhile to wait until those conditions are met. Otherwise, you’ll have spotty germination and stunted, spindly plants. Beans grow so quickly that waiting for ideal temperatures will be worth some patience.

Cucumbers

Warm, light, sandy loam soils are preferred for early production. Compost and composted manure is good. Cukes like moist well drained, fertile soil and need a pH above 6.0. A farmer says: Apply 6 to 10 pounds of fertilizer for each 100 foot of row, using care not to bring fertilizer into contact with the seed. A home gardener says: When I plant cukes, I dig out a hole, about a foot square, fill it with compost, and plant my seed right into the compost. No fertilizing the rest of the season and you’re not wasting fertilizer in soil between plants that the roots never touch.

A tropical vegetable, cucumbers thrive when the weather is hot and water is plentiful. If the weather is unseasonably cool, you can wait a while to mulch until the ground is warmed by the sun.

Sow seeds directly in the garden when daytime temperatures are at least 65 to 75 degrees. They are frost tender and should not be planted until the soil has warmed up to 65, some say 70 degrees! Cukes grow well in daytime temperatures in the 70’s, best at 81 F to 101.

Mini FYI: The inside of a cucumber can be up to twenty degrees cooler than the outside temperature. This is where the saying cool as a cumber came from!Eggplant

Wherever you plant them, the key word for eggplant soil is ‘rich.’ Sandy loam or loam is lovely. Eggplants are greedy feeders; ideal eggplant soil is well-drained, rich in organic matter, including lots of well-rotted manure, and has about a neutral in pH. During the season, sidedress with extra compost. Keep the soil moist to promote maximum growth.

Eggplant do NOT thrive in very humid areas. Pollination is difficult when the weather conditions are very wet, overly humid or excessively hot.

The minimum soil temp needed for seed germination is 60 F. The optimum range is 75-90 F.
Transplant at soil temp that is minimum 65F.

Place transplants in the garden slightly deeper than they were in their pot. Cold soil will shock the plant and set it back several weeks.

Eggplants are more susceptible than tomato plants to injury from low temperatures and do not grow until temperatures warm. They like temps to remain above 68 degrees, 70 to 85° F is even better.

Critical temperature for setting out eggplants isn’t the daytime high, but the nighttime low. Cool evenings will set back the seedlings’ growth and make them more susceptible to diseases. Wait until the evening temperatures are above 65 degrees before putting in seedlings. Cold temperatures will stop plant and root growth reducing plant vigor and yields. If your crop is still producing in the fall, cover them on cold evenings to extend the harvest.

Don’t be in a rush to mulch. Mulching too early in the season keeps the soil cool, resulting in slow growth, poor fruit set, and shallow rooting.

Peppers, either hot or bell, need VERY RICH SOIL, are heavy feeders! Place compost, worm castings, rotted manure under them when transplanting. Mix in 1 T Epsom Salts, Maxi Crop, Landscape Mix. Sandy soils are preferred for the earliest plantings because they warm more rapidly in the spring. Heavier soils can be quite productive, provided they are well drained and irrigated with care.

Rather than in the soil, do foliar Epsom Salts! A cheap home remedy that can keep plants greener and bushier, enhance production of healthier fruit later in the season, and potentially help reduce blossom-end rot. Apply 1 tablespoon of granules around each transplant, but research has shown a foliarspray of a solution of 1 tablespoon Epsom salts per gallon of water at transplanting, first flowering, and fruit set is more effective! As a foliar spray, Epsom salts can be taken up quickly by plants, otherwise, it is sometimes hard for the plant to get it out of the soil because of calcium competition.

Peppers are Temp Particular! Hot peppers grow best in daytime air temperatures 65° to 85°F. Transplant when night time temperatures stay above 50 degrees, 55 is better. Below that plants grow very slowly, have yellowish, puckered leaves, and look sickly, often don’t recover. Night temps between 60° and 70° are best. In temperatures greater than 85°F, peppers may drop their blossoms although set fruit will ripen. The ideal temperature for peppers is a daytime temperature around 75°F and a nighttime temperature around 62°F.

At soil temperatures above 65 degrees, pepper growth accelerates. Plants may become stunted and never recover if either the soil or air temperature is much below 55 degrees.

Nighttime temperatures below 60 F or above 75 F can reduce fruit set.

Plumping up! Gardeners in hot regions will need to be especially patient with big bells and sweet roasting peppers. Both of these tend to wait until the nights are longer and cooler in late summer before fruiting and plumping up. These folks may want to plant banana peppers or sweet non-bells, which will ripen in time to use with those bumper crops of tomatoes and basil. Peppers need time on the plant to absorb nutrients and water and plump up their flesh, so pack your patience.

Color Changes! Mother Earth News says: After reaching their maximum size, green peppers that are meant to turn red, will develop red pigments in 10 to 28 days, if daytime temperatures are between 65 degrees and 75 degrees. In southern regions where temperatures exceed that range, peppers turn yellowish and may acquire an off-color pallor that is not attractive. Below the optimum temperature range, color development slows dramatically; below 55 degrees, it stops completely. If soil temperatures drop below 68 degrees, pigment production declines and eventually ceases.

Squashes grow best in full sun! They like rich well-drained soil, high in organic matter, and require a high level of feeding. Zucchini, in particular, produce a lot and get hungry!

Days need to be at least 70 degrees and nights to dip no lower than 40 degrees. Summer squashes grow best in air temperatures ranging from 60° to 75°F.

Plant in a warm soil. If the soil is below 60 degrees F., summer squash seeds are more likely to rot in the ground before sprouting. The ideal soil temperature for germination is 70-90 degrees F. A doable temp is 65-70F.

Tomatoes

Add a good dose of animal manures and compost, and my usuals – a huge handful of bone meal, a handful of non-fat powdered milk, worm castings, a tad of coffee grounds to the planting holes. This robust combo works well. As they decompose, coffee grounds appear to suppress some common fungal rots and wilts, including FUSARIUM! Go VERY LIGHTLY on the coffee grounds. Too much can kill your plants. It was found in studies, what worked well was coffee grounds part of a compost mix, was in one case comprising as little as 0.5 percent of the material. That’s only 1/2 a percent!

True, tomatoes are heat lovers, but per the University of NV, temperatures over 104 F, for only four hours, causes the flowers to abort! If you expect high summer temps, plant heat tolerant (“heat set”) varieties: Florasette, Heat Wave, Solar Set, Sunchaser, Sunmaster, Sunpride, Surfire. When temps are out of your tomatoes’ happiness range, they abort fruit set and go into survival mode, stop production. That’s why your plant may make no tomatoes for a period of time. Don’t think it is a quitter and pull it. It will start up again when temps lower.

High nighttime temps are even worse than high daytime temperatures because your plant never gets to rest.

In the spring, wait until nighttime temperatures are reliably above 55 F or protect your plants with a cover at night.

Many seeds can be presprouted. Presprouting is super and clever because you know you have plants! Germination in the soil can be spotty, so get fresh seed from a reliable source and presprout! It’s easy and terrific fun to watch the little ones appear! See more

Regions have huge variances in planting time strategies, and even in the same yard there are micro niches that vary considerably, so get a thermometer and plant in the right place at the right time! See more

With your Soil Thermometer, and good gardener self discipline, get your seeds and plants in the ground at their most productive times for your location! Here’s to abundant harvests!

The Green Bean Connection started as correspondence for SoCal Santa Barbara CA USA Pilgrim Terrace Community Garden. All three of Santa Barbara city’s community gardens are very coastal. During late spring/summer we are often in a fog belt/marine layer most years, locally referred to as the May grays, June glooms and August fogusts. Keep that in mind compared to the microclimate niche where your veggie garden is. Bless you for being such a wonderful Earth Steward!